Studies of the history of personal hygiene and health behavior have generally neglected one of the areas of greatest concern to both health professionals and lay people, from antiquity to the present, that of intestinal purity. Anxiety over bowel health has spawned a remarkable number and variety of theories and practices among orthodox medical workers, alternative healers, physical educators, health journalists, food and exercise faddists, purveyors of quack drugs and devices, and manufacturers of health foods and equipment. Analysis of the evolution of professional and popular attitudes and behavior will thus not only enlarge historians' understanding of the development of hygiene, but also clarify the structure and functioning of health culture in England and America. In addition, the evolution of inner hygiene is the ideal vehicle for tracing the rise of the concept of diseases of civilization from the late eighteenth century to current theories relating dietary fiber to "Western diseases." The project will be accomplished through the extensive examination of documents both published (books, journals, magazines, pamphlets, advertisements) and unpublished (memoirs, correspondence, government files) in the United States and England.